Part B: Quantitative

Problems when Vf = 0

4. A 7 kg. bowling ball traveling down a test track at 8 m/s hits a pile of
dirt, and comes to a halt after 0.01 seconds.

a. Find Av and mav.

b. With what impact force did the bowling ball hit the pile of dirt?

(a)

(b)

5600 N

Explanation:

Change in velocity, is expressed as

Where v represent the velocity and subscripts f and i represent final and initial respectively. Given that the ball finally comes to rest, its final velocity is taken as 0. Substituting 0 for final velocity and the given figure of 8 m/s for initial velocity then the change in velocity is given by

To find the change in momentum, then we substitute 7 kg for m and -8 m/s for therefore

(b)

The impact force, F is equivalent to ma where m is the mass of the ball and a is the acceleration. Here, acceleration is given by dividing the change in velocity by time ie

Substituting t with 0.05 s then

Since F=ma then substituting m with 7 Kg we get that F=7*-800=-5600 N

Therefore, the impact force is equivalent to 5600 N

your answer is yx

hope this

~mia

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s